Fernando Torres sniffed out the goal that kept Chelsea in Europe but was still left with his nose out of joint. A topsy-turvy outing for the Spaniard was the main feature of a match that ended in a victory that his club clearly craved but which could yet prove costly.

These are intriguing times at Stamford Bridge. Rafael Benítez understandably accentuated the positive after a night on which his team came from behind to beat an impressive Steaua Bucharest side and Torres ended an epic barren spell but still took a battering to both his nose and his confidence. Torres scored a fine goal in the 71st minute but then missed a late penalty.

Chelsea's progress to the quarter-finals of the Europa League condemns them to frantic cramming for the end of the campaign, with the FA Cup replay against Manchester United on 1 April meaning Chelsea must contest six matches in 16 days after next week's international break. That is sure to test the resilience and depth of the team that currently sits fourth in the Premier League as they strive to avert the ignominy of missing out on Champions League qualification.

"Top teams want to be in all competitions until the end," said an undaunted Benítez. "Since I came here I think we are playing around nine games each month. We knew it would be difficult but we have confidence in the players and hopefully we can manage well and progress in all of them."

The manager was similarly upbeat about Torres's penalty miss, claiming that the fact that the beleaguered striker felt like taking it was more significant than that his shot bounced back off the crossbar.

Last season Torres eschewed a spot kick at Birmingham when he was enduring a fruitless spell but this time, having scored to claim only his second goal of 2013 – the other was against Brentford in the FA Cup – he stepped up. "I am pleased that he took the responsibility more than he missed the penalty," said Benítez. "That is good for his confidence and for the future." The miss came moments after Torres's nose had been bloodied in a collision with the boot of Steaua's Lukasz Szukala.

Torres's confidence was bolstered by a goal that was sweetly taken and decisive. It came 19 minutes from time, when Eden Hazard deftly helped a Juan Mata pass on to Torres, who showed admirable sharpness to sidestep Szukala and fire into the far corner of the net from 10 yards. That completed a turnaround that was far from simple for Chelsea.

Benítez, whose quest for some silverware to show from his interim reign meant he was determined not to sacrifice this competition for the sake of the league, named a much stronger line-up than the one that started last week's 1-0 defeat in Bucharest, but their hopes of making an early breakthrough were thwarted by the relentless pressing of the dynamic visitors.

Steaua should have opened the scoring from their first attack, when Mikel John Obi was dispossessed midway inside his own half and John Terry failed to cut out a through-ball to Raul Rusescu, who scampered through on goal, only to be denied by Petr Cech's agility.

Chelsea finally forced Steaua's goalkeeper into action in the 16th minute, when Ciprian Tatarusanu comfortably collected a Mata free-kick. Steaua, increasingly confident as Chelsea struggled to match their energy, broke straight down the other end and Alexandru Bourceanu curled a 25-yard shot just wide. This was not a side that had come solely to cling on to their first-leg lead.

Hazard was Chelsea's chief early threat, constantly wriggling and probing for openings. In the 22nd minute he dribbled down the right before setting up that rarest of phenomena, a shot on target from Mikel. Tatarusanu repelled the Nigerian's 20-yard drive.

When Chelsea eventually raised their intensity, they got a goal. Oscar won the ball on halfway and slipped it through to Mata, who evaded one tackle before offloading to Ramires and darting into the box to take the return pass and slot the ball under Tatarusanu from 15 yards.

Chelsea looked to take charge. Torres fired wide from 16 yards and then Tatarusanu batted away a bullet from Hazard following lovely interplay between the Belgian and Mata.

But Chelsea knocked off early for half-time and Steaua punished them. A 45th-minute corner was poorly dealt with by Chelsea, with Torres and Ramires failing to get decisive touches at the near post, leaving Cristian Tanase to shoot from close range. Cech scrambled that effort off the line but Vlad Chiriches reacted first to slam the ball into the roof of the net for a potentially damaging away goal.

Benítez looked agitated on the sideline but apparently was not sufficiently alarmed to make substitutions at the interval. Steaua also opted to carry on as before and that looked wise as they enjoyed the better of the second half. It took a set piece in the 58th minute for Chelsea to edge back in front, Terry heading into the net from seven yards after a Mata free-kick from the left. Then Torres took centre stage to settle the tie and leave his state-of-mind and Chelsea's season fascinatingly cluttered.